model fluid command


model fluid <b > keyword

Primary keywords:

active    list    time-total    follower    substep    timestep

Set parameters for a fluid flow analysis. This command is only available model configure fluid has been specified. The activity can be directly specified by providing b. See the ref:-Fluid-Mechanical Interaction <fluid-mechanical>- section for complete information. :flag3:[cs: commmon]`

active b

The fluid process is on, by default, when the model configure fluid command is given. Specify active off to suppress fluid calculations.


Display fluid calculation-mode information.

time-total f

f is the accumulated fluid time for the model. This can be reset to any value, and will continue to be accumulated during cycling after that.

follower b

Specify that fluid mode is to be considered a follower, and cycled to equilibrium after each leader step has been taken.

substep i

Specify the maximum number of steps the fluid process will take when solving with follower on.


The stable timestep is calculated automatically. This is the default setting.

fix f

Set the timestep to be the fixed value f. All timestep calculations are skipped. Setting a value greater than the calculated critical timestep will result in an error.

increment f

Set the incremental amount that the timestep is allowed to increase from one cycle to the next in auto mode. By default, f = 1.05. The timestep can decrease by any amount to ensure stability.

maximum f

Set the maximum allowed timestep. By default, there is no bound to the maximum timestep.

safety-factor f

Set the timestep safety factor, or the factor that is multiplied by the stable timestep calculated when auto mode. By default, f = 1.0.

update i

Set the number of cycles between timestep calculation in 3DEC. By default, i = 1 (i.e., the timestep is updated every cycle). This value is not used in FLAC3D fluid timestep calculations.